British light heavyweight Buatsi secured a victory yet underwhelming beginning to his career under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate likely gained him a majority decision in a close ten-round fight at the Co-op Live Arena.
But Parker had his moments, landing some telling single shots in a fight where the styles failed to mesh, with frequent clinching marring the fight.
The officials scored it 96-94 for to the winner, with the remaining official a 95-95.
"It wasn't my greatest display but what defines champions? They win," the victor stated in the ringside as he was greeted with disapproval from the audience.
The Londoner got back to winning after his initial pro loss - an thrilling contest with his previous opponent in last winter - to earn a twentieth professional win.
Some ringside observers thought Parker, 31, deserved the victory but the British boxer suffered the second defeat of his 28-match professional journey.
Buatsi Claims Win in Dull Affair
The fighter's advancement has stalled in recent years through contract problems and considerable time of lack of fights.
Earlier forecast as the next star of British boxing, he now stands trying to realize his potential - possibly in what feels like a last chance - under new promotional backing.
He opened tentatively, with both competitors ready to take risks in a cagey early stages.
The challenger, whose single earlier setback came at super-middleweight against his former opponent in two years ago after damaging his hand in the contest, was participating in his second fight at light heavyweight.
By the fight's midpoint, Parker had made it competitive, creating difficulties for Buatsi, who worked behind a tight guard to barely take the cleaner periods.
The audience's tolerance decreased during constant clinching, with the challenger going down several times during close exchanges.
Parker ended stronger, but many rounds were hard to judge. Nevertheless, previous titleholder Carl Frampton - providing analysis for the broadcast network - had it particularly wide for the challenger, scoring for Buatsi just one round.
The victor advances, but with the presence of power puncher David Benavidez, and Russian star Bivol ruling the division, the journey to titles - on this evidence - still seems difficult.
Hatton Memorial Motivates Local Rivalry Battle
In the secondary fight, Arthur defeated Bradley Rea by split-decision in a outstanding all-Manchester battle to capture the European light heavyweight title.
The venue fell silent for a profoundly moving tribute ahead of the contest as 10 bells sounded in remembrance of local hero Hatton, who passed away aged 46 in September.
It was the premier televised fight night in the location since Hatton's passing. As the concluding sound ended, the stillness gave way to a roar of "there's only one Hatton".
The fighting within the ring reflected the emotion. The eventual winner was knocked down by a left hook flush on the face in the initial stage, rising shakily to his feet on the eight count.
But the red-colored equipment of the fighter soon came forward again. From the other corner, the opponent - in opposing blue - was damaged soon, heavy swelling developing under his face as the pair landed punishing blows.
The challenger, twenty-seven, landed power punches but the champion, thirty-four, responded in kind with stinging uppercuts as the pace hardly diminished over 12 rounds.
The victor narrowly won the verdict with scoring tallies of 114-114, narrow lead and 115-112, but each competitor were persistent and full of heart, all the qualities their hero the legend stood for.
